The inventor of the diesel engine, Rudolph Diesel—1897, used “natural gas” as a diesel engine fumigant fuel charge. Fumigation of a diesel engine is the addition of a gaseous fuel to the intake air charge of a diesel engine. Development of diesel engine fumigation techniques has continued, such as that disclosed in Ritter et al. U.S. Pat. No. 6,901,889.
The pre-heating of diesel fuel to improve combustion efficiency and reduce exhaust gas pollutants has been active since the 1930's. Hypergolic diesel combustion received significant attention in the 1980's. More recently Tavlarides et al. U.S. Pat. No. 7,488,357 and others disclose methods and apparatus which cause diesel fuel to become supercritical prior to injection into the combustion chamber.
U.S. Pat. No. 4,892,561 to Levine discloses fuels for internal combustion engines which contain at least 50% by weight of methyl ether.
U.S. Pat. No. 5,632,786 to Basu et al. describes a method for operating a spark ignition internal combustion engine utilizing an improved composition containing dimethyl ether and propane as fuel.
U.S. Pat. No. 6,095,102 to Willi et al. teaches a dual fuel engine which creates a substantially homogeneous mixture of gaseous fuel, air, and pilot fuel during a compression stroke.
U.S. Pat. No. 6,145,495 to Whitcome discloses a propane injection system for a diesel engine.
U.S. Pat. No. 6,202,601 to Ouellette et al. describes a method and apparatus for dual fuel injection into an internal combustion engine. A main fuel is ignited by a pilot fuel that is more readily flammable than the main fuel.
U.S. Pat. No. 6,206,940 to Weissman et al. teaches fuel formulations to extend the lean limit.
U.S. Pat. No. 6,213,104 to Ishikiriyama et al. discloses supplying fuel to an internal combustion engine in a supercritical state by raising the pressure and the temperature of the fuel above the critical pressure and temperature.
U.S. Pat. No. 6,286,482 to Flynn, et al. describes a premixed charge compression ignition engine with combustion control.
U.S. Pat. No. 6,324,827 to Basu et al. teaches a method of generating power in a dry low NOx combustion system.
U.S. Pat. No. 6,607,567 to Towfighi discloses propellant gas for tools operated by combustion power on the basis of combustible gases containing a mixture of 40% to 70% by weight of dimethyl ether, nitrous oxide and/or nitromethane, 8% to 20% by weight of propylene, methyl acetylene, propane and/or propadiene and 20% to 45% by weight of isobutane and/or n-butane.
U.S. Pat. Nos. 6,901,889 and 7,225,763 to Ritter, et al. describes a system and method to reduce particulate and NOx emissions from diesel engines through the use of a duel-fuel fumigation system.
U.S. Pat. No. 7,488,357 to Tavlarides, et al. teaches a composition of diesel biodiesel or blended fuel with exhaust gas mixtures or with liquid CO2. The composition is in a liquid state near the supercritical region or a supercritical fluid mixture such that it quasi-instantaneously diffuses into the compressed and hot air as a single and homogeneous supercritical phase upon injection in a combustion chamber.
UK Patent GB 2460996 discloses a combustion method for very low Cetane Number (CN) materials.
UK Patent GB 2460997 discloses a heated combustion air cycle to increase the efficiency of combustion of renewable oils and fats.
United States Pub. No. 2012/0318226 by applicant herein discloses a method for supercritical diesel combustion. The foregoing application is incorporated by reference in its entirety as if fully set forth herein.
The foregoing patents reflect the current state of the art of which the present inventor is aware. Reference to, and discussion of, these patents is intended to aid in discharging Applicant's acknowledged duty of candor in disclosing information that may be relevant to the examination of claims to the present invention. However, it is respectfully submitted that none of the above-indicated patents disclose, teach, suggest, show, or otherwise render obvious, either singly or when considered in combination, the invention described and claimed herein.